Line Item Builder
Builds a set of structured lines with calculations across them — the shape of a quotation, an order or an invoice.
Where to find it
Architect Panel → Data:
- Datastores — the datastore, then Table Designer to add or edit a field
Architect Panel → ERP - Setup:
- Documents — transactional documents, which may suit better
What it is for
Repeating lines where each has the same columns and the set has a total. Description, quantity, unit price, line total — and a sum at the bottom.
It differs from the plain repeating field by understanding that lines have columns and that columns can be calculated.
What it stores
The lines together as text on the parent record. Like the other repeating types it does not join, so individual lines are not records.
Should this be a datastore instead?
The question to ask before choosing a repeating field, and the one people wish they had asked. Repeating rows inside a field are convenient and they are not records — they cannot be reported on individually, cannot be searched as records, cannot carry their own permissions, and cannot be linked to from anywhere else.
The test: will anybody ever ask a question about the rows rather than about the parent? "How many lines mention this product", "which of these are outstanding", "show me every one across all records" — if any of those will be asked, the rows want to be a datastore of their own with a link back to the parent.
Converting later means migrating data out of a field and into records, which is real work. Deciding early costs nothing.
For line items specifically, that question is usually "will anybody ask what we sold most of?" — and if the answer is yes, lines want to be records.
Consider transactional documents instead
The platform has a document layer built exactly for quotations, orders and invoices — with numbering, conversion between document types, ledger posting, tax handling and multi-currency.
If you are building anything commercial, start there rather than assembling it from a line item field. This field is right for a lightweight case: a simple list with a total on a form that is not part of a trading process.
Get the calculations right at the edges
Rounding is where line-based calculations go wrong. Rounding each line before summing gives a different total from summing and rounding once, and both are defensible — but they must agree with whatever else in your business calculates the same figure.
Decide, write it down, and check the total against a hand calculation before anybody relies on it.
Prices change
If a line captures a price, decide whether it is a snapshot or a live lookup. A quotation must keep the price quoted; a live lookup means an old quotation silently revalues, which is a genuine commercial problem.
Snapshot is nearly always what you want, for the same reason time entries store their rate and stock issues store their cost.
Keep the columns few
Lines are entered horizontally and columns compete for width. Beyond five or six the layout suffers, particularly on a smaller screen, and entry becomes fiddly.
Validate per line
A zero quantity, a negative price, a missing description. Catching these at entry is far better than a total that is wrong for a reason nobody can see.
Worked example
An internal requisition form uses a line item builder for a handful of items with a total — no numbering, no ledger, no conversion, so the field is a good fit. The organisation's customer quotations use transactional documents instead, because those convert to orders, post to the ledger and need per-line reporting.
Recommendations
- Use transactional documents for anything commercial.
- Snapshot prices, do not look them up live.
- Settle the rounding rule and verify the total by hand.
- Five or six columns at most.